Sir Osis of Liver:
For as long as I've been here, I've never seen the ad at top of forum. Used adblockplus for many years, more recently been using IE11 tracking protection. Ad wasn't there earlier today, now it is. If I disable/enable tracking protection, it sometimes disappears for one refresh, sometimes not. Looks like it's being served from SM adserver. Just curious, was something changed?

CoreISP:
Is it always a couple or even one of the same banner(s) that does end up loading? If so, that/those ad(s) is/are being served directly from our adsystem rather than from Google, and the ones you're likely not seeing upon refresh is one served from Google/DC which your plugins blocks.

If your browser does not block our adsystem (good! Make sure to whitelist *.simplemachines.org in your AdBlocker folks! ;) Advertising income helps us run the place.) then you should have sporadically seen some NameCheap banners for example as well in those many years. However, some of the campaigns currently running do have a setup that may make it show more often than other banners would, whilst the NC banner is shown less frequently and this all combined also causes Google Ads to be loaded fewer times than normal; which is why perhaps now you're noticing it whilst you didn't notice a banner loading sometimes before as it was more sporadically. (Our adsystem is sometimes a bit slow, so...)Unless its just you switching to IE11/IE's tracking protection that's the reason, as that's the thing that also changed. :P

As our adsystem is not a tracker but merely a piece of software deciding which campaign to show, I'd imagine IE11's tracking protection ignores it. A good adblocker will likey detect our advertising system and block the banners served directly from our adsystem as well. (Which is why whitelisting our domain is such a nice idea if you're using an AdBlocker. :P Our adsystem is friendly.)

Sir Osis of Liver:
I've never seen any ad on this forum except when I had blocker disabled. I'm seeing the same ad again today, it's coming from adsystem.simplemachines.org. IE tracking protection has, up til now, been blocking ads here 100%, same as adblockplus.

Just reinstalled tracking protection lists from here, sometimes ad displays, sometimes it doesn't, always same ad. Not seeing anything different on other sites that are ad heavy. Wierd.

SaltedWeb:
I thought it was just me, same thing... I was like now thats odd..... maybe its Ad gremlins

CoreISP:
Yeah so as I said: it isn't blocking our own adsystem, just Google. :P